package bin_tree.leetcode;

/**
 * @author yuisama
 * @date 2023/03/24 20:14
 **/
public class Num101_IsSymmetricTree {
    public boolean isSymmetric(TreeNode root) {
        if (root == null || root.left == null && root.right == null) {
            return true;
        }
        return isMirror(root.left,root.right);
    }
    // 判断两颗树t1和t2是否是轴对称相等的树
    private boolean isMirror(TreeNode t1, TreeNode t2) {
        if (t1 == null && t2 == null) {
            return true;
        }
        if (t1 == null || t2 == null) {
            return false;
        }
        if (t1.val != t2.val) {
            return false;
        }
        return isMirror(t1.left,t2.right) && isMirror(t1.right,t2.left);
    }
}